The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 30, 1999
Filed:
Apr. 10, 1996
Applicant:
Inventor:
Robert A Doll, Glendale, WI (US);
Assignee:
Applied Power Inc., Butler, WI (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F16K / ;
U.S. Cl.
CPC ...
13762538 ; 25112907 ;
Abstract
A bidirectional on/off spool valve has circumferentially-extending through-slots in a spool which are axially alignable with circumferentially-extending grooves in the main bore. The slots and grooves create a flow path through the valve which minimizes Bernoulli forces that tend to close the valve or create negative Bernoulli forces which help keep the valve open. The spool has a stop wall at its closed end which restricts the open area of the lumen of the spool and a balance tube extends forwardly from the stop wall to equalize the pressure behind the stop wall with the pressure in front of the stop wall, so that the spool is not locked in the open position.